Cerebral embolism (CE) from either cardiac or aortic sources, and carotid atherothrombosis, are the most common mechanism of ischemic stroke. Cerebral embolism is diagnosed and treated based on indirect clinical evidence. Detection of microemboli with Doppler ultrasound is reliable and reproducible, and is feasible in stroke patients. Our pilot data in stroke patients show a higher prevalence of embolic signals in groups believed at highest risk for recurrent events. Embolic signals at the time of stroke also appear to predict an excess risk for subsequent poor outcome. Inadequate longitudinal data exist documenting the clinical importance of cerebral embolic signals (CES) detected by this method. This study will, 1) evaluate the association of the presence, persistence, or appearance of CES to the risk of recurrent stroke or death in patients with acute ischemic stroke, and 2) evaluate the effect of therapeutic interventions on the presence, persistence, or appearance of CES. The prevalence of CES will be assessed in a cohort of 425 ischemic stroke cases. Participants will be recruited from North Carolina Baptist Hospital during years 1-3, and will be studied for common carotid, middle cerebral, or vertebro-basilar CES, as well as neurologic status, at baseline, 1 week, 1 month, and 3 months. The cohort will be followed for morbid and mortal events to 1 year. Longitudinal follow-up will assess: persistence or appearance of CES; the association between CES and recurrent stroke or death, and the effect of therapies on CES. This study will improve understanding of the clinical importance of CES in a high risk population. This may allow more accurate identification of patients at excess risk, providing an opportunity to intervene with different preventive strategies.